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December 3, 2013

Men And Women’s Brains Are ‘Strikingly’ Complimentary

by redOrbit Staff & Wire Reports - Your Universe Online

redOrbit Staff & Wire Reports - Your Universe Online

Men and women have ‘striking’ differences in their neural wiring that might explain some of the behavioral differences between the two sexes, according to a study published Monday in the Proceedings of National Academy of Sciences.

The study was one of the largest to date to create to compare the connectomes, neural maps of the brain, of men and women.

The results revealed that men have far greater neural connectivity from front to back and within one brain hemisphere, suggesting their brains are structured to facilitate connectivity between perception and coordinated action. However, in females, this wiring goes between the left and right brain hemispheres, suggesting that women facilitate communication between the analytic and intuitive parts of the brain, the researchers said.

"These maps show us a stark difference – and complementarity – in the architecture of the human brain that helps provide a potential neural basis as to why men excel at certain tasks, and women at others," said study leader Ragini Verma, PhD, an associate professor in the department of Radiology at the Perelman School of Medicine at the University of Pennsylvania.

For instance, on average, men are more likely better at learning and performing a single task at hand, like cycling or navigating directions, whereas women have superior memory and social cognition skills, making them better equipped for multitasking and creating solutions that work for a group. In other words, they have what's called a mentalistic approach.

The human brain is a complex roadmap of neural pathways linking many networks that help us process information and react accordingly, with behavior controlled by several of these sub-networks working in conjunction.

Although previous research has revealed gender differences in the brain, the current study is the first to show the neural wiring connecting regions across the whole brain among a large population.

Verma and colleagues investigated the gender-specific differences in brain connectivity during the course of development in 949 study participants – 521 females and 428 males aged 8 to 22 years – using something known as diffusion tensor imaging (DTI). This water-based imaging technique can trace and highlight the fiber pathways connecting the different regions of the brain, laying the foundation for a structural connectome or network of the whole brain.

The researchers found that females displayed greater connectivity in the supratentorial region, which contains the cerebrum, the largest part of the brain, between the left and right hemispheres. Males, on the other hand, displayed greater connectivity within each hemisphere.

However, the opposite prevailed in the cerebellum, the part of the brain that plays a major role in motor control, where males displayed greater inter-hemispheric connectivity and females displayed greater intra-hemispheric connectivity, the researchers said.

These connections likely give men an efficient system for coordinated action, where the cerebellum, which involves perception, and the front of the brain, which involves action, are bridged together, the researchers said.

The female connections likely facilitate integration of the analytic and sequential processing modes of the left hemisphere with the spatial, intuitive information processing modes of the right side.

Interestingly, the researchers observed only a few gender differences in the connectivity in children younger than 13 years of age, while the differences were more pronounced in adolescents aged 14 to 17 and young adults older than 17.

The study’s findings were consistent with a previous Penn University behavior study that demonstrated pronounced sexual differences. In that study, of which the current work is a subset, the researchers found that females outperformed men on attention, word and face memory, and social cognition tests, while males performed better on spatial processing and sensorimotor speed. Those differences were most pronounced in the 12 to 14 year age range.

"It's quite striking how complementary the brains of women and men really are," said study co-author Dr. Ruben Gur, PhD, a professor of psychology at the University of Pennsylvania.

"Detailed connectome maps of the brain will not only help us better understand the differences between how men and women think, but it will also give us more insight into the roots of neurological disorders, which are often sex related."

The researchers say their next steps are to quantify how an individual's neural connections are different from the population as a whole, and to identify which neural connections are gender specific and common in both. They also plan to confirm their findings through functional magnetic resonance imaging (fMRI) studies.